Glass containers, including glass bottles, are formed in a process that is well-known in the art. The various components of the glass are heated until they have melted. A gob of this melted glass is next formed into a parison in a so-called blanking or parison mold. The parison formed is moved from the parison mold to a finishing or blow mold, where the finished bottle is shaped.
Mass production of glass bottles is generally carried out in a well-known IS (individual section) glass forming machine which has a plurality of glass forming means integrated into a single plural-section machine fed by a single source of molten glass. The sections are operated in synchronism in such relative phase relationship to permit the several sections to acquire gobs of molten glass in ordered sequence from the single source.
Thus, as one of the sections is receiving a gob from the feeding means, another section is delivering a finished article to an output conveyor and other sections are engaged in various forming steps between receipt of the gob and production of the finished article. The sequence of operation is controlled by a timing mechanism that may be either mechanically or electronically controlled. This timing mechanism sequentially initiates mechanical devices in a predetermined synchronized sequence through automatic control systems.
The IS machines have two types of molds in each individual mold section whereby a gob is received in a first mold, called a parison mold, for the initial process of forming a parison, followed by transfer of the parison to a second mold, called the blow or finishing mold, for blowing the parison to its final configuration. A transfer arm is pivoted between the parison mold and the finishing mold, and the parison is formed in an inverted position in the parison mold and is transferred to the finishing mold in an upright position. This process is generally disclosed in U.S. Pat. No. 3,762,907, incorporated herein by reference.
The parison and finishing molds are subjected to extremely high temperatures. For example, the parison mold can reach temperatures as high as 1200.degree. F. or more, while the finishing mold can reach temperatures as high as 1100.degree. F. As a result, the heat that is transferred to these molds by the gob of molten glass during the molding process cannot be adequately dissipated into the ambient air by convection without slowing down the process.
A variety of auxiliary cooling means or methods have been utilized for these molds. U.S. Pat. No. 4,983,203 issued to Erb et al., and assigned to the assignee of this application, discloses a glass forming system wherein parison mold halves are movable between a retracted position and a closed position at a parison-forming station. A pair of neck ring mold halves forming a neck ring mold are held together at the parison-forming station and are configured for nesting surrounding engagement by the parison mold halves when brought together. The parison mold halves are provided with a number of vertical interior cooling passages generally peripherally disposed within each parison mold half. Mold air supply plenums are provided disposed below each mold half at the retracted station. During the period that the mold halves spend in the retracted state, they are continuously cooled by air flowing from the plenum up through the individual mold cooling passages. This system provides for cooling of the parison mold halves, but relies upon the physical contact between the cooled parison mold halves and the neck ring molds for neck ring mold cooling during the parison-forming operation. The heating of the neck ring mold during cyclic operation of such a glass forming machine has proven to be the speed-limiting factor. A significant reduction of the neck ring mold temperature would allow increased speed of operation.
U.S. Pat. No. 4,629,488, issued to Doud et al., discloses a cooling system for cooling a neck ring mold and the parison mold in the portion of an individual section glass molding machine in which the parison is formed. The means for cooling the neck ring mold and the parison mold includes a plurality of first cooling holes in an upper receiver cap, a plurality of second cooling holes in the neck ring mold that communicate with the plurality of first cooling holes, and a plurality of third cooling holes in the parison mold that communicate with the plurality of second cooling holes. Specifically, the neck ring mold is cooled by a flow of cooling air that flows upwardly through a plurality of vertically disposed and circumferentially spaced second cooling holes in the neck ring mold, and is cooled by a portion of the cooling air flowing radially out through the radially disposed notches in the neck ring mold. The cooling is carried out on the parison mold side of the glassware forming machine since the neck ring mold is on the parison side about 80% of the time during normal operation. In addition, the neck ring mold receives more cooling than the parison mold since it provides mechanical strength and stability to the finish portion.
The Doud system is complex to machine, and hence costly. Additionally, it requires a source of compressed air to be supplied to an inlet port which implies either a rapid plug-in and withdrawal air supply system for each neck ring mold, or in the alternative, a carry-along high pressure manifold which will allow the neck ring mold to be moved from the parison-forming station to the final forming station. Here again, additional complexity is engendered, and a possible loss of reliability through high pressure seal failure may be expected
U.S. Pat. No. 4,659,357, issued to Doud, also discloses an apparatus and method for cooling the neck ring mold and parison mold. In this patent, the cooling system utilizes fan air from a fan box for cooling the neck ring mold, thus eliminating the expense of providing compressed air for cooling. Specifically, the neck ring mold is cooled by a flow of fan air that flows upwardly through a plurality of vertically disposed and circumferentially spaced cooling holes in the neck ring mold, and is cooled by a portion of the cooling air flowing radially out through the radially disposed notches in the neck ring mold. The remainder of the fan air is directed upwardly through a plurality of vertically disposed and circumferentially spaced cooling holes in the parison mold. Here again, an expensive series of passages must be machined for each particular design of neck ring mold.
U.S. Pat. No. 4,813,995, issued to Knoth et al., discloses an apparatus for manufacturing containers out of glass which has a cooling means comprised of a ring of nozzles by which jets of cooling air are directed to the neck ring mold portion of the parison mold. The neck ring mold is cooled during heating of the parison to prevent the neck portion of the parison from flowing and causing the collapse of the parison to the bottom of the parison mold cavity. The parison mold itself has an internal cavity to which cooling air is supplied. The air leaves the chamber through cylindrical passages formed in the mold. Here optimal cooling efficiency cannot be secured because the air reaching the neck ring mold is already severely preheated by its passage through the parison mold.
It is an object of the invention to provide a simple low cost way of providing adequate cooling to a neck ring mold at a parison-forming station.